The Basics of How the Heart Functions

1
Conduction and Contraction

• In the Human Heart

2
Purpose of the Heart

• Pump Blood
• Enable Oxygen and Nutrient Delivery
• Force Blood Into the Lungs
• Force Blood Through the Body

3
Cardiac Anatomy

• Four Total Chambers
• Smaller Atria on Top
• Larger Ventricles on Bottom
• Valves Prevent Backflow
• Nodes That Regulate Contractile Signals
• Nerves That Carry Contractile Signals

4
Cardiac Conduction

• Impulse Created in Sinoatrial Node
• Travels Through Atria Towards Ventricles
• Causes Contraction as it Travels
• Passes Through Atrioventricular Node
• Travels Along Nerves Through the Ventricles

5
Coordinated Contraction

• Gap Junctions Between Cells in a Chamber
• Provides a Means For Rapid Signal Transmission
• Special Nerves in Ventricles Known as Purkinje
  Fibers
• Carry Contractile Signals Faster Than Any Other
  Nerve
• All Cells in a Chamber Contract Together

6
Coordination

• Ensures That the Atria Contract Before the
  Ventricles
• Moves Blood in the Proper Direction
• Allows For Maximum Contractile Effort
• Increases Stroke Volume
• Delivers More Oxygen and Nutrients

7
Effects of Damage

• Improper Conduction
• Inefficient Contraction
• Decreased Oxygen and Nutrient Delivery
• Fatigue
• Death

8
Evaluation

• Electrocardiogram
• Echocardiogram
• Stress Tests
• Holter Monitoring
• Performed by EKG Technician

9
References

• http//www.ekgtechniciansalary.org/
• http//www.ekgtechniciansalary.org/ekg-rhythms/